78Q8392LA03-28CH/F

Overview

The 78Q8392L/A03 is a low power Ethernet coaxial transceiver designed as a replacement for the 78Q8392L/A02. It provides the interface between single-ended coaxial cable signals and Manchester-encoded differential logic signals, supporting IEEE 802.3 10Base5 and 10Base2 standards. The device integrates analog transmit/receive buffers, a 10 MHz on-board oscillator, timing logic for jabber and heartbeat functions, output drivers, bandgap reference, current reference, and collision detection. It operates with a supply voltage of -9V ± 5% and is available in lead-free 16-pin plastic DIP and 28-pin PLCC packages.

Feature Summary

• Integrates all transceiver functions including receiver, transmitter, collision detection, jabber timer, and heartbeat function.
• Compliant with Ethernet II, IEEE 802.3 10Base5, and 10Base2 standards.
• Includes squelch circuitry at all inputs to reject noise and ensure valid data detection.
• Features externally selectable collision detect (CD) heartbeat operation compatible with IEEE 802.3 repeaters.

Applications

• Internal or external Medium Attachment Unit (MAU) environments
• Ethernet 10Base5 thick coaxial network interfaces
• Ethernet 10Base2 thin coaxial network interfaces

Procurement Notes

Verify the package type matches the design requirements, as the component is available in both 16-pin Plastic DIP and 28-pin PLCC configurations. Confirm that the ordering suffix corresponds to the specific package variant needed for the PCB layout. Ensure the source documentation aligns with the Teridian Semiconductor Corporation specifications provided in the datasheet.

Selection Notes

Select the 78Q8392L/A03 when upgrading from the 78Q8392L/A02, as only a single resistor value change is required for compatibility. Choose the 16-pin DIP or 28-pin PLCC package based on board space and pinout constraints. Ensure the design accommodates the -9V supply requirement and includes necessary isolation transformers for the AUI interface connections.

Part Context

This component is part of the 78Q8392L series of Ethernet transceivers manufactured by Teridian Semiconductor Corporation, now associated with Analog Devices Inc./Maxim Integrated. It serves as a direct functional successor to the 78Q8392L/A02 model, maintaining compatibility while offering low power consumption characteristics suitable for standard Ethernet coaxial applications.

Replacement Considerations

The 78Q8392L/A03 is explicitly documented as a replacement for the SSI/TDK/Teridian 78Q8392L/A02. Upgrading requires changing only one external resistor value. No other cross-model substitutes are verified in the provided documentation.

FAQ

How does the 78Q8392L/A03 differ from the previous generation 78Q8392L/A02?

The 78Q8392L/A03 is a replacement for the 78Q8392L/A02. The primary hardware modification required for an upgrade is a change in a single external resistor value.

What is the function of the HBE pin?

The HBE (Heartbeat Enable) pin controls the CD Heartbeat function. It enables the heartbeat when grounded or left open, and disables it when connected to VEE.

How is the internal operating current established?

A fixed 976 Ω 1% resistor must be connected between the RR+ and RR- pins to establish the internal operating currents.